On Sun, Dec 15, 2013 at 10:58 PM, Maria Stevens <mariastevens...@gmail.com> wrote: > On Fri, Dec 13, 2013 at 3:58 PM, Maria Stevens <mariastevens...@gmail.com> > wrote: >> >> >>> > So, Only case 1 is working for me. I am not using any custom >>> > gnuradio-block in >>> > my receiver. Major blocks in my demodulator chain consists of FIR >>> > filters, >>> > gr_pfb_clock_sync_ccf and packet decoder along with some adders >>> > subtractors >>> > etc. what is the difference caused by the same demodulator chain when >>> > reading >>> > data directly from usrp source and from file source? is it because some >>> > of the >>> > demodulator chain blocks are causing back pressure due to taking too >>> > much time >>> > in processing but when run in real time it causes data loss during >>> > exchange of >>> > samples between blocks.? I am confused if in real time the >>> >>> > gr_pfb_clock_sync_ccf block or any other major block stucks in >>> > processing >>> > during which samples are lost due to new incoming samples. >>> >>> Are you observing overflows? If so, have you tried reducing the >>> bandwidth and see if that helps? >> >> >> Thanks for your reply. I am not observing any overflows. I am using 500k >> sample rate. My system specs are 6GB RAM core i7 ubuntu 12.04. >> >> What could be the issue ? >> >> Regards. >> M.S. > > > Any comments on this issue? Anything that i can try to cater this issue? > > Regards > MS
I would agree with Martin. It sounds like you're dropping samples form the USRP, so it's strange to hear you say you aren't seeing and overflow indications. The only thing else I can think of is that there's a sample rate mismatch somewhere in the chain. And from your original email, I'm assuming that you don't have a throttle in your flowgraph when using the USRP? If you can publish the simplest form of a transmit and receive flowgraph we could look at or use to test, that might help understand this better. Tom _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
